Fungicides control various phytopathological diseases by interrupting various metabolic pathways within the fungal organism. Thus different fungicides may control the same disease, but by different modes of action. Many organisms, however, can develop resistance to a particular mode of action over time. Thus, having available fungicides which act by various modes of action is important to adequately control most diseases.
One mode of action is the inhibition of the succinate dehydrogenase (SDH) enzyme in the respiratory pathway of fungi. This mode of action has previously been demonstrated for control of basidiomycetes. For example, carboxin, is a commercially available fungicide which exhibits the SDH inhibitory mode of action against various basidiomycetes. Drouhot et al. ["Properties of Botrytis cinerea Mitochondria and Effects of Various Toxicants Including Fungicides," Pesticide Science, 30:415-417, 1991] have suggested that such a mode of action for control of ascomycetes, such as Botrytis sp., is needed to overcome resistance problems. In their tests of respiratory inhibition, carboxin exhibited a 68% inhibition at 1 .mu.M concentration and was judged the best fungicide of those tested for SDH mode of action against Botrytis.
Pyrazolecarboxamide fungicides are known in the art. U.S. Pat. No. 4,214,090 (Huppatz, Jul. 22, 1980) discloses various N-(phenyl)pyrazolecarboxamides. U.S. Pat. Nos. 4,742,074 (May 3, 1988, Nishida et al) and 5,093,347 (Mar. 3, 1992, Graneto et al) dis-close various N-(substituted-indanyl)pyrazole-4-carboxamides, U.S. Pat. No. 5,223,526 discloses pyrazole carboxanilides and German DE 42 31 517 discloses various heterocyclic N-(2-substituted phenyl) carboxamides useful as fungicides for various agronomic diseases.
It is an object of this invention to provide novel compounds having a high level of activity in SDH inhibition in ascomycetes. It is a further object of this invention to provide compounds having a broad spectrum of activity against fungal diseases of plants. It is a further object of this invention to provide methods of controlling or preventing fungal diseases of plants. It is a still further object of this invention to provide fungicidal compositions useful in carrying out those methods. The present inventions include surprising and unexpected advantages over previously known fungicides.
These objects are accomplished by providing a combination of substituents not heretofore appreciated including a sterically demanding group, which is a selectively substituted cyclohexyl alpha to an anilide linkage. This sterically demanding group provides a heretofore unknown advantageous effect.